[Bug]: Using `animation()` Atom modifier on iOS16 causes a crash.

[kenmaz]

Checklist

• This is not a bug caused by platform.
• Reviewed the README and documentation.
• Checked existing issues & PRs to ensure not duplicated.

What happened?

Using .animation() on iOS16 simulator and actual device causes a crash.
You can reproduce this bug by modifying one line in Example app.

--- a/Examples/Packages/CrossPlatform/Sources/ExampleCounter/ExampleCounter.swift
+++ b/Examples/Packages/CrossPlatform/Sources/ExampleCounter/ExampleCounter.swift
@@ -8,7 +8,7 @@ struct CounterAtom: StateAtom, Hashable {
 }
 
 struct CounterScreen: View {
-    @Watch(CounterAtom())
+    @Watch(CounterAtom().animation())
     var count
 
     var body: some View {

Note that it works well on both iOS17 and 18

Expected Behavior

It should not crash.

Reproduction Steps

1. Add .animation() modifier to any Atom
2. Run it on iOS 16 simulator or actual iOS16 device
3. Crash it when the atom is watched

Swift Version

Swift 6

Library Version

0.8.1

Platform

iOS

Scrrenshot/Video/Gif

[ra1028]

It seems that it crashes in the hashing of the atom key that contains SwiftUI.Animation. The conformance of it to 'Hashable' is only available in iOS 17+, so it implicitly causes app crashing in iOS 16. Surprisingly, no warnings showed up when using synthesized Hashable comformance, but it shows Conformance of 'Animation' to 'Hashable' is only available in iOS 17.0 or newer if you explicitly write hash(into:) like below:

private let animation: Animation?

public func hash(into hasher: inout Hasher) {
    hasher.combine(animation)
}

Hashing Animation into the atom key is the core of atom modifiers, so I'd have to give up to support iOS 16 for this modifier, unfortunately.
That said, it's already planned to drop support for iOS 16 in the next major release. Let me keep this bug as is for now.

Thanks for reporting anyways @kenmaz